A cellular communications network includes multiple base stations. In order for the network to provide the best possible coverage for users, it is necessary for the radio configuration of each base station to take into consideration the radio configurations of nearby base stations. For example, the downlink power with which each base station transmits signals needs to take into account the downlink powers used by nearby base stations, in order to ensure that there is adequate network coverage, without causing problems due to interference.
Traditionally, the radio configuration of cellular networks is manually planned, and explicitly provisioned from the network to a macrolayer NodeB. As a development of this, as disclosed in GB-2447439A, standalone femtocell base stations can instead be provisioned with a range of possible values for their radio configuration, and can then choose an optimal configuration autonomously. In addition, GB-2472597 discloses a femtocell base station that is intended to form part of a group of base stations that can be deployed in an enterprise such as a large office, a shopping mall, a campus, or the like. In this solution, small groups of femtocell base stations that are connected to the same local area network (LAN) may autonomously reach a collective radio configuration by broadcasting their own selected configuration to all their peers, and then adjusting their own configuration based on the configurations of their peers that they receive.
However, this has the limitation that the femtocells must all be connected to the same local area network, so that they can communicate by broadcasting (or multicasting their configuration information messages). Moreover, in the case of a large deployment of small cells, there is the disadvantage that every femtocell basestation must handle signalling traffic from every other femtocell basestation.